I took delivery of two iPhone 4s today (you can see some photos of them on Flickr), and I’m really enjoying the device so far. The screen is impressive, and FaceTime works every bit as well as advertised.
There have been reports of a loss of signal strength when the phone is held in your left hand such as to cause your palm (for example, the major crease of your thumb) to cover the bottom part of the left side of the device – presumably electrically connecting the two separate sections of the exterior case, which are split at that point and two others.
I did a few tests here, and I can indeed reproduce the issue, so I wanted to post my findings. Summary: I completely lose the 3G signal, but Wi-Fi and 2G are unaffected – and I’ve had no dropped calls.
First, my situation here is that, with appropriate antennae activated on the phone:
- I have 5 bars of wi-fi.
- I have 5 bars of 3G coverage.
- I have 5 bars of 2G coverage, and GPRS attachment.
So, pretty much the ideal situation. I’m at my home office in Edinburgh, Scotland (UK), and my iPhone is on the O2 UK network.
In my tests, I never dropped a call. I did, however have signal degradation as I’ll describe. In each case I was calling from my iPhone 4 to my land-line here, answering the land-line, and leaving the call open. I then wandered around the house, checking signal fluctuation both when trying to trigger the issue and when holding the phone flat in my hand, not touching the sides.
I didn’t experience any significant signal loss whilst moving around when I wasn’t attempting to trigger the issue (I did experience a minor fluctuation in 3G, from 5 bars occasionally down to 4 bars, but that’s always been true in this building). The results below show what happened when I did try to trigger the issue.
| 3G active | Wi-Fi active | 3G Signal loss | 2G signal loss | Call dropped |
|---|---|---|---|---|
| No | No | - | No | No |
| No | Yes | - | No | No |
| Yes | No | Yes | No | No |
| Yes | Yes | Yes | No | No |
The results above show that I only experienced 3G signal loss, with no loss of 2G connectivity. In each relevant case my calls were unaffected; I didn’t drop a call at any point. 3G signal loss seems to occur regardless of the state of the Wi-Fi antenna or its connection status.
The loss of 3G signal was admittedly extreme: I lost at least 4 bars (i.e. at best my 3G signal strength was 1 bar of a possible 5, after triggering the issue). In four out of five tests, 3G connectivity would disappear entirely (having previously been at 5 bars).
After placing my hand in the appropriate position to cause the issue, I experienced complete 3G signal loss within an average of less than 10 seconds. In a couple of tests, it would first lose a bar, then another bar, then drop away entirely – but most times it fell away completely within seconds.
If your findings differ from this (I know for example that several people have indeed experienced dropped calls, as shown in the various videos of the issue on the internet), make sure you report them to Apple. It’s been observed that the “Bumper” cases for iPhone 4 (made by Apple) ameliorate the issue since they obviously keep your conductive skin separated from the metal edge of the phone using a layer of plastic.
I’m not overly worried about the issue at the moment, since it doesn’t seem to affect my voice calls and I’m a right-handed caller anyway, and I’m very pleased with the iPhone 4 and iOS 4 in general. We’ll see what happens, and what response Apple may make – I just wanted to share my own experience with you.
For what it’s worth, I didn’t encounter the issue at all until I’d read about it then deliberately tried to reproduce it. I love the phone, and I’d still highly recommend it.
[...] This post was mentioned on Twitter by Matt Legend Gemmell, Martin Dufort, bwinton, Alfons Hoogervorst, Mohammad Abdurraafay and others. Mohammad Abdurraafay said: See, I said already! I follow some great peeps on twitter. Read: http://abr.vg/l/35 by @abrahamvegh & http://j.mp/99W6Nq by @mattgemmell [...]
Since I got a 3GS last year I haven’t been looking at the iPhone 4, but I’ve been reading about this, trying to decide between shock and bemusement. Thanks for pointing out that you had to actually try to create the problem: that’s not something I’d read yet, and it makes a lot more sense.
That’s going to be more of a problem in places that only have 3g (or, rather, that have UMTS but no 2g GSM), like Japan.
I can reproduce the signal loss.
I have a SIM-free iPhone 4 – came today – on UK Vodafone.
Covering the band on the lower left of the phone results in 2G signal (not in a 3G area) dropping from 4 bars to zero.
The phone displays ‘Searching…’ and is unable to make calls. I’ve not tested it during a call yet.
I’ll probably just buy a bumper as the rest of the phone is great.
As per my blog post http://fscked.co.uk/post/731907113/iphone4-signal, I can sometimes reproduce the symptoms but haven’t recorded any effect on either voice calls or 3G network throughput yet. Thanks for the thoughtful post, Matt, at a time when most blogs covering this issue are just rehashing bland content.
[...] Matt Legend Gemmell did some testing of his own and confirmed that touching the area on the bottom left would reliably and sharply cut 3G [...]
[...] new iPhones were delivered early to many who preordered on June 15. Developer Matt Legend Gemmell did some testing of his own and confirmed that touching the area on the bottom left would reliably and sharply cut 3G signal [...]
[...] Matt Legend Gemmell did some testing of his own and confirmed that touching the area on the bottom left would reliably and sharply cut 3G [...]
I tried it and also had it fall down to “searching..” tho I never tried to make any calls.
Im hoping apple can fix this as it seems like a major oversight.
[...] In the case of Insanely Great Mac, this caused calls to be dropped.Developer Matt Legend Gemmell did some testing of his own and confirmed that touching the area on the bottom left would reliably and sharply cut 3G [...]
[...] I did a few tests here, and I can indeed reproduce the issue, so I wanted to post my findings. Summary: I completely lose the 3G signal, but Wi-Fi and 2G are unaffected – and I’ve had no dropped calls. source [...]
The same thing happens on my iPhone 3G, which also has a wrap-around antenna but no break in the metal. Anyone with an older iPhone should try it as well and see what happens.
IMHO the phone loses signal due to its defective design. Attempting to blame the user is.. Jobbo’s prerogerative. It harks back to the days when users had to have special training to use the badly designed and expensive software that nerds wrote for them. Jobbo FAIL.
There seem to be 2 possible causes for the problem:
1/ Holding the phone in hand impairs in a dramatic way physical performance of the antenna. This would be a fatal design flaw. Let’s hope Apple is not SO incompetent and irresponsible as to release a device with such a flaw although one never knows…
2/ Holding the phone in hand affects mildly performance of the antenna (which is an inevitable physical effect) but phone software fails to process correctly the change and effectively shuts down transmission. This seems to be a more likely scenario because tuning this kind of software to all possible conditions and changes of conditions is a daunting and unfortunately error prone task even for a company with the resources of Apple.
There is a simple way to test which of the above is true : shut the phone entirely down and then start it while holding it in the offending way. Thus software will work from the very beginning under the offending physical conditions rather than trying to adapt to a change (and fail on that if second theory is correct).
[...] Matt Legend Gemmell did some testing of his own and confirmed that touching the area on the bottom left would reliably and sharply cut 3G [...]